This could get interesting.

It was an incendiary allegation — and a mystery of great intrigue in the media world: After the publishing powerhouse Judith Regan was fired by HarperCollins in 2006, she claimed that a senior executive at its parent company, News Corporation, had encouraged her to lie two years earlier to federal investigators who were vetting Bernard B. Kerik for the job of homeland security secretary.

Ms. Regan had once been involved in an affair with Mr. Kerik, the former New York City police commissioner whose mentor and supporter, former Mayor Rudolph W. Giuliani, was in the nascent stages of a presidential campaign. The News Corporation executive, whom she did not name, wanted to protect Mr. Giuliani and conceal the affair, she said.

Now, court documents filed in a lawsuit make clear whom Ms. Regan was accusing of urging her to lie: Roger E. Ailes, the powerful chairman of Fox News and a longtime friend of Mr. Giuliani. What is more, the documents say that Ms. Regan taped the telephone call from Mr. Ailes in which Mr. Ailes discussed her relationship with Mr. Kerik.

It may be corporate policy at Fox News to lie or just make stuff up, but when you do it to federal investigators, they have a way of making your life miserable and your lawyer very rich.